Tubing.



Patent efl Feb. l3, i900. F. F. BISCHDFF.

T U B l N G.

(Application filed May 15, 1899.)

(No Model.)

FREDERICK F. BISCHOFF, OF CHICAGO, ILLINOIS, ASSIGNOR TO ROBERT K.

HILL, LOUISE STA'ILER, AND ANNA MAIER, OF SAME PLACE.

TUBING.

SPECIFICATION formingpart of Letters Patent No. 643,459, dated February 13, 1900.

Application filed May 15, 1899.

T0 to whom it may concern:

Beitknown thatLFREDnmcKF.B1soH0FF, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Tubing; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to a novel construction in a tube, the object being to provide a cheap, light, strong, and durable tube for constructive purposes and likewise for use where an air-tight or water tube is not essential; and it consists in the features of construction and combinations of parts hereinafter fully described and claimed.

In the accompanying drawings, illustrating my invention, Figure 1 illustrates a blank which when bent forms the tube. Fig. 2 is a transverse section of a finished tube on the line 2 2 of Fig. 3. Fig. 3 is a longitudinal section of same on the line 3 3 of Fig. 2.

My tube is formed by first cutting a blank A from sheet metal, which is provided on opposite edges with pairs B C D E, 850., of ears or projections F, which are bent at about right angles to said blank A and are brought into alinement with each other when said blank is bent to form the tube said pair C of said ears or projections F fitting between the pairs B and D thereof and said pair D fitting between the pairs C and E. when said ears or projections have been so brought into alinement, a strip G of sheet metal, provided with slots I-I equal in length to the combined Width of two adjacent ears or projections F, is inserted into the tube and the said ears or proj ections passed through said slots H, and then each ear or projection is bent or folded over so as to form a hook in which said strip is firmly clamped. In this manner the blank is firmly jointed at its meeting edges and is there strongly reinforced, so that its compression strength is equal to seamless tubing. My

Serial No. 716,812. (No model.)

tubing also has the great advantage that it is very cheap compared with seamless tubing. By means of providing the opposite edges of said blank with alternate pairs of ears the finished tube obtains far more torsional strength than with any other arrangement of the ears.

I claim as my invention- 1. A tube formed of a bent strip of sheet metal having lugs on its meeting edges, and a reinforcing-strip extending along the line of junction of said edges, said lugs being passed through slots in said reinforcing-strip, and clenched, substantially as described.

2. A tube formed of a bent strip of sheet metal having lugs on its meeting edges, and a reinforcing-strip extending along the line of junction of said edges, said lugs being passed through slots in said reinforcing-strip, and clenched, said lugs being arranged in alternate pairs, substantially as described.

3. A tube formed of a bent strip of sheet metal having lugs on its meeting edges, and a reinforcing-strip extending along the line of junction of said edges, said lugs being passed through slots in said reinforcing-strip, and clenched, said lugs being arranged in alternate pairs, said slots in said strip being each of sufficient length to receive two of said lugs, substantially as described.

4. A tube formed of a bent strip of sheet metal having lugs on its meeting edges, and a reinforcing-strip extending along the line of junction of said edges, said lugs being passed through slots in said reinforcing-strip, and clenched, said slots being of sufficient length to receive two of said lugs, and said lugs being bent over in opposite directions, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

FREDERICK F. BISCHOFF.

Witnesses:

RUDOLPH WM. Lo'rz, E. F. WILsoN. 

